Comments: Named for town of Ada, Pontotoc Co, OK. Type area lies within and to west of Ada; outcrop extends from northern edge of Stonewall quad, north of Vamoosa, southwestward to a point about 3 mi southeast of Roff. Is in Pontotoc and Seminole Cos, OK, Chautauqua platform and Arkoma basin.(Morgan,1924) Average thickness 100 ft. Limestone conglomerates and coarse sandstones very prominent in greater part of outcrop. Clastic material decreases to north; near Vamoosa very scarce.With decrease in amount of clastics northward, formation becomes thinner--only 60 ft thick at northern edge of quad. Also contains light-colored shales. Conglomerates and sandstones are characteristically saturated with asphalt; north of Canadian River, asphaltic strata less numerous than to south. Source of asphalt unclear; possibly heavy oil from exposed asphaltic sands of Simpson formation was brought out and deposited. Fossils rare. Near base is a thin black limestone that is very persistent near Ada.